Wonder how a police officer will act if they should encounter a person with a home made pistol be with no s/n for them to run.
Will they try and arrest you for having a gun with altered s/n for something like that.
I know most police officers don't know the law all that well. I had one tell me I can't hunt with a handgun and he would arrest me if he saw me carrying one in the woods. I had to show him the hunting regulations. He learned something new that day.
Might as well ask the same question with regards to a pre 1968 firearm, since serial numbers were not required until 1968, and there are a hell of a lot more pre 1968, unseiralized, firearms than there are home built firearms.